Polyoxygenated anti-inflammatory biscembranoids from the soft coral Sarcophyton tortuosum and their stereochemistry

Five novel biscembranoids, ximaolides H–L (1–5), were isolated from the Hainan soft coral Sarcophyton tortuosum. Compounds 1 and 2 are the first examples of biscembranoids bearing a 135-bridged lactone moiety, 4 is the first biscembranoid comprising an uncommon oxetane ring, and 5 represents the first 36-peroxyl biscembranoid.